Multi-media is the hottest topic in the computer industry today. It is widely proclaimed as the next revolution in computing. The reason multi-media is "hot," is the potential for humanizing information.
Multimedia implies the ability to integrate multiple forms of data in a computer environment. The various data forms include: audio, image, motion video, graphics, text and animation. Due to the volume and variety of data which must be managed within the internal structure of a computer and ultimately presented to the user, new methods for managing that data through the display interface need to be developed.
For instance, in the area of still image graphics, when windows are overlaid upon one another, a paramount consideration is that a higher level window take priority over a lower level window. In other words, a lower window's image should not show through to a higher window overlaid on top of the lower window. Normally, the windows have a display priority. The window with the highest priority is displayed on top of all other windows. As a result, some windows are obscured or partially obscured by other windows.
However, techniques used in still image graphics do not lend themselves to displaying multiple windows, overlaid upon one another, displaying dynamic images (motion video). Software techniques are too slow to meet the real-time requirements of motion video data. Typically, display of video data requires a processor capable of performing 120 million operations per second when displaying video images at a rate of 30 frames per second on a 1024 by 768 pixel screen.
Most software techniques, typically used for displaying static window images, are inadequate to decide on a pixel-by-pixel basis whether to display or discard a pixel in real-time. Thus, trying to decide whether to display a pixel or discard a pixel in an overlaid multi-media window environment with multiple media windows requires the need for real-time presentation.
Typically, hardware assistance such as a pixel map look-up table is employed to determine in real-time whether a given pixel is to be displayed or discarded in a multi-media, overlaid multi window environment. However, the costs involved are currently prohibitive due to the amount of storage space required. For instance, a 1000.times.1000 pixel screen requires the mapping of 2 million bits of pixel information. Additionally, a pixel map look-up table is limited to serve only a few windows, typically a maximum of 4 windows. The number of windows is limited by the amount of memory. Furthermore, the expense involved in order to display multiple windows displaying dynamic images, utilizing a pixel map look-up table is exorbitant due to memory restrictions.
Therefore, what is needed is a window manager device that uses significantly less storage space than a pixel map look-up table and is able to process multiple windows displaying motion video data in real time.